Water-based colorant preparations

ABSTRACT

The invention relates to aqueous colorant preparations containing A) between 0.1 and 50 wt. % of at least one organic and/or inorganic pigment and/or at least one organic colorant. B) between 0.01 and 80 wt. % of at least one naphthol-oxyalkylate sulfopropyl ether, one alkanol-oxyalkylate sulfopropyl ether or one alkylphenol-oxyalkylate sulfopropyl ether. C) between 0 and 30 wt. % of at least one organic solvent. D) between 0 and 20 wt. % of other standard derivatives and E) between 10 and 90 wt % of water, respectively in relation to the total weight (100%) of the colorant preparation. The colorant preparation is used, for example, in printing inks, especially ink jet printing inks.

[0001] The present invention relates to waterborne colorant dispersions,a process for their production, their use as recording fluids,especially for the ink jet printing process, and also their use inelectrophotographic toners, especially polymerization toners, in powdercoatings and in color filters.

[0002] The ink jet printing process, like for example electrophotography(laser printers and copiers), is a nonimpact printing process and hasbecome more and more important, especially in the small office, homeoffice (SOHO) sector, owing to the increasing use of computers.

[0003] Ink jet printing technology distinguishes between the so-calledcontinuous printing processes and the drop-on-demand processes, thedrops in question being ink drops which are generated by acomputer-controlled electrical signal. There are basically two kinds ofdrop-on-demand ink jet processes, namely thermal ink jet, also known asbubble jet, and piezoelectric ink jet. Whereas in thermal ink jet thepressure wave which leads to the expulsion of a drop of ink from anozzle of the print head is generated by the input of thermal energy viaa heating element, piezoink jet printing utilizes the spontaneous shapechange of a piezoelectric crystal on application of a voltage signal togenerate the pressure wave needed. Both piezoelectric and thermal inkjet are notable for a high technical standard for the production ofcolored images of high optical quality or even photoquality and are alsosuitable for the production of large format prints at high rates ofprinting speed.

[0004] Thermal and piezoelectric ink jet have hitherto employed inkswhich are based on solutions of water-soluble dyes, which is why theprints possess high brilliance and optical density, but insufficientlightfastness and poor water resistance. These disadvantages ofdye-based ink jet inks can only be partly overcome by the use ofspecialty papers. One way of overcoming the aforementioned disadvantagesof dye-based inks would be to use pigmented inks.

[0005] Pigmented inks for ink jet printing would have to meet a wholeseries of requirements. They have to have a viscosity and surfacetension suitable for printing, they have to be stable in storage, iethey should not coagulate and the dispersed pigment should not sediment,they must not clog the printer nozzles, which can be problematical inthe case of pigment particle inks especially, and they should beenvironmentally friendly, ie be substantially waterborne and containvery low concentrations of organic solvents. Similarly, the purity ofthe preparations has to meet high requirements, since excessiveconcentrations of inorganic or organic salts and ions, especiallychloride ions, lead to corrosion and hence to premature destruction ofthe print heads or in the case of bubble jet printers to harmfuldeposits on the heating elements.

[0006] High standards are required especially of the color strength, thehue, the brilliance, transparency and fastness properties, for examplelightfastness, waterfastness and crockfastness of the pigments andprints. High lightfastness is important especially when the ink jetprocess is to be used to produce prints of photographic quality or foroutdoor use.

[0007] A fine state of subdivision is a basic prerequisite for pigmentpreparations for use in ink jet printing, since the avoidance of nozzleclogging requires that the average pigment particle size not exceed 200nm and that the particle size distribution be very narrow, so that eventhe maximum particle size does not exceed 500 nm. As well as a finestate of subdivision, it is particularly the flocculation resistancewhich is a very important quality criterion of an ink jet preparation,which is why crystal growth or agglomeration of the pigment particleshas to be effectively prevented by means of suitable additives. This isusually accomplished by means of certain dispersing assistants. Apigment dispersion property closely related to its flocculationresistance is its stability in storage, since the pigment particles mustnot agglomerate during prolonged storage, even at elevated or reducedtemperatures compared with room temperature. During printing, pigmentedinks are subjected to extreme thermal and mechanical stresses; thedispersing assistant has to ensure pigment dispersion stability even inthese circumstances. Transient temperature jumps of up to 500° C. occurin thermal ink jet. Even in these conditions, the pigment may neitherflocculate or cogate (sediment) on the heating elements of the printernor clog the printer nozzles. In printing, the pigmented ink is flungthrough a narrow nozzle; extremely high shearing stresses occur in theprocess, but they must not cause the dispersing assistant to be shearedoff the pigment surface.

[0008] Accordingly, the dispersing assistant used is of decisiveimportance, not only because it determines the physical properties, forexample surface tension and viscosity, of the dispersions, but alsobecause it shall stabilize the inks against flocculation in the courseof storage and decomposition in the course of the printing operation.

[0009] Prior art pigmented preparations for ink jet printing often failto meet printer manufacturers' requirements in that they are deficientin subdivision, thermal stability and stability in storage.

[0010] Especially the stability problems of pigmented ink jet inks areclosely tied to adequate stabilization of the pigment particles in theaqueous organic solutions.

[0011] It is known from WO 99/01517, U.S. Pat. No. 6,077,339 and EP 1054 045 A1 that especially the alkoxylation products of phenol-styrenecondensates and their derivatives that have been ionically modified, iecompletely or partially converted into sulfuric monoesters using sulfurtrioxide or chlorosulfonic acid, and neutralized using alkaline agentsare useful as dispersing assistants which are suitable for theproduction of pigment preparations for ink jet inks.

[0012] It is therefore an object of the present invention to providecolorant preparations which are readily dispersible and stable instorage and, in particular, have good printing properties in the ink jetprinting process.

[0013] This object is achieved, surprisingly, by the use ofwater-soluble sulfopropyl ethers of alkoxylated naphthols, alkanols oralkylphenols as dispersants in colorant preparations.

[0014] These sulfopropylated dispersions are significantly more suitablefor producing pigment preparations for ink jet printing than, forexample, the sulfuric monoesters of alkoxylated phenol-styrenecondensates that are described in WO 99/01517, U.S. Pat. No. 6,077,339or EP 1 054 045 A1 since the storage stability of the pigmentpreparations, even at elevated temperature, is substantially improved.In addition, the sulfopropyl ethers are very pure, compared with thesulfuric monoesters, owing to the different kind of synthesis, so thatthey are substantially free of inorganic salts and especially the halidecontent is very low. A low concentration of halide ions, especially ofchloride ions, reduces the corrosion of the print heads. A furtheradvantage is that the dispersants of the present invention have no cloudpoint, ie there is no risk of phase separation and flocculation athigher temperature with these dispersants.

[0015] The present invention accordingly provides colorant preparationsconsisting essentially of

[0016] A) 0.1 to 50% by weight and preferably 1 to 30% by weight of atleast one organic and/or inorganic pigment and/or at least one organicdye,

[0017] B) 0.01 to 80% by weight and preferably 0.1 to 50% by weight ofat least one naphthol alkoxylate sulfopropyl ether, alkanol alkoxylatesulfopropyl ether or alkylphenol alkoxylate sulfopropyl ether

[0018] C) 0 to 30% by weight and preferably 0.1 to 15% by weight of atleast one organic solvent,

[0019] D) 0 to 20% by weight and preferably 0.1 to 5% by weight offurther customary additives,

[0020] E) 10 to 90% by weight and preferably 20 to 60% by weight ofwater, each percentage being based on the total weight (100% by weight)of the colorant preparation.

[0021] Component (A) is a finely divided organic or inorganic pigmentand/or an organic dye or a mixture of various organic and/or inorganicpigments and/or organic dyes. The pigments can be used not only in theform of dry powders but also as water-moist presscakes.

[0022] Useful organic pigments include a monoazo, disazo, laked azo,β-naphthol, Naphtol AS, benzimidazolone, disazo condensation, azo metalcomplex pigment or a polycyclic pigment, such as for example aphthalocyanine, quinacridone, perylene, perinone, thiazineindigo,thioindigo, anthanthrone, anthraquinone, flavanthrone, indanthrone,isoviolanthrone, pyranthrone, dioxazine, quinophthalone, isoindolinone,isoindoline or diketopyrrolopyrrole pigment or carbon black.

[0023] Useful inorganic pigments include for example titanium dioxides,zinc sulfides, iron oxides, chromium oxides, ultramarine, nickel- orchromium antimony titanium oxides, cobalt oxides and bismuth vanadates.

[0024] Useful organic dyes include acid dyes, direct dyes or reactivedyes; in the case of reactive dyes, dyes which have been reacted withnucleophiles can be used as well.

[0025] The pigments used should be very finely divided, in thatpreferably 95% and more preferably 99% of the pigment particles have aparticle size ≦500 nm. The average particle size is preferably <200 nm.Depending on the pigment used, the morphology of the pigment particlescan vary widely, and accordingly the viscosity behavior of the pigmentpreparations can vary widely as a function of the particle shape. Toobtain a favorable viscosity behavior for the preparations, theparticles should preferably have a cuboid or spherical shape.

[0026] A selection of particularly preferred organic pigments are carbonblack pigments, for example lampblacks or furnace blacks; monoazo,disazo and benzimidazolone pigments, especially the Colour Indexpigments Pigment Yellow 17, Pigment Yellow 74, Pigment Yellow 83,Pigment Yellow 97, Pigment Yellow 120, Pigment Yellow 128, PigmentYellow 139, Pigment Yellow 151, Pigment Yellow 155, Pigment Yellow 180,Pigment Yellow 213, Pigment Red 57:1, Pigment Red 146, Pigment Red 176,Pigment Red 184, Pigment Red 185 or Pigment Red 269; phthalocyaninepigments, especially the Colour Index pigments Pigment Blue 15, PigmentBlue 15:3 or Pigment Blue 15:4 and quinacridone pigments, especially theColour Index pigments Pigment Red 122 or Pigment Violet 19.

[0027] A selection of particularly preferred organic dyes are the ColourIndex dyes Acid Yellow 17, Acid Yellow 23, Direct Yellow 86, DirectYellow 98, Direct Yellow 132, Reactive Yellow 37, Acid Red 52, Acid Red289, Reactive Red 23, Reactive Red 180, Acid Blue 9 and Direct Blue 199.

[0028] Component (B) of the colorant preparations according to theinvention comprises at least one water-soluble dispersing assistantbased on a water-soluble completely or partially sulfopropylatedalkoxylated naphthol, alkanol or alkylphenol.

[0029] Preferred dispersing assistants are compounds of the formula (II)and also their mixtures with compounds of the formula (I)

[0030] where

[0031] R1 and R2 are identical or different and are each a C₁-C₁₂-alkylradical which may contain polar groups such as alcohol groups, aminegroups, keto groups, amide groups or ester groups, or are each a phenylradical or H,

[0032] R3 is a C₁-C₄-alkyl radical or a phenyl radical, preferablymethyl,

[0033] m is from 0 to 50, preferably from 0 to 30, especially from 1 to20,

[0034] n is from 1 to 100, preferably from 2 to 50, especially from 5 to30, subject to the proviso that n≧m;

[0035] X is a singly positively charged ion, for example the ion of analkali metal such as Li, Na, K, Rb or Cs, or a hydrogen ion or anammonium ion or a mono-, di-, tri- or tetraalkylammonium ion.

[0036] Preferred compounds of the formulae (I) and (II) are those whosealkoxy chain is in the beta position of the naphthol (β naphthols). Thealkoxy radicals —(CH₂—CHR³—O—)_(m) and —(CH₂—CH₂—O—)_(n) can each bepresent as a block or as a random distribution in the chain.

[0037] The dispersing assistants preferably contain 0 to 50% by weightof molecules of the formula (I) and 50 to 100% by weight of molecules ofthe formula (II).

[0038] Particularly preferred compounds of the formulae (I) and (II) arethe compounds of the formulae (III) and (IV)

[0039] where m, n and X are each as defined above.

[0040] The preferred dispersing assistants contain 0 to 50% by weight ofmolecules of formula (III) and 50 to 100% by weight of molecules of theformula (IV).

[0041] As well as the completely or partially sulfopropylatedalkoxylated naphthols, it is also possible to use completely orpartially sulfopropylated alkoxylated alkanols or completely orpartially sulfopropylated alkoxylated alkylphenols as dispersingassistants. In these compounds too the use of the sulfopropyl groupingensures significantly better storage stabilities and viscosityproperties compared with the conventionally used terminal carboxylate,phosphate or sulfate groups.

[0042] The colorant preparations according to the invention maytherefore also include compounds of the formula (VI) and their mixtureswith compounds of the formula (V)

[0043] where m, n and X are each as defined above and

[0044] R4 is R5 or

[0045] where R5 is a linear or branched C₁-C₂₄-alkyl radical which maycontain polar groups such as alcohol groups, amine groups, keto groups,amide groups or ester groups.

[0046] The dispersing assistants mentioned may contain 0 to 50% byweight of molecules of the formula (V) and 50 to 100% by weight ofmolecules of the formula (VI).

[0047] The synthesis of the dispersing assistants used according to theinvention is in itself literature known and carried out in two steps.The first step has the naphthols, alkanols or alkylphenols alkoxylatedby reaction of the corresponding naphthoxides, alkoxides oralkylphenoxides with alkylene oxides at elevated temperature in ananionic polymerization. This synthetic step is analogous to the stepinvolved in the preparation of sulfosuccinic monoesters of alkoxylatednovolaks that is described in EP 0 065 751 A1 or analogous to thealkoxylation step which is described in DE 196 44 077 A1 for thepreparation of ionically modified phenol-styrene polyglycol ethers. Inthe second step, the alkoxylated naphthols, alkanols or alkylphenols areconverted under relatively mild, weakly basic conditions with1,3-propanesultone into the corresponding sulfopropylated alkoxylatednaphthols, alkanols or alkylphenols (Peter Köberle: “Sulphobetaines andEthersulfonates: Unique Surfactants via Sulfopropylation Reactions”; in:Industrial Applications of Surfactants IV; D. R. Karsa, Ed.; The RoyalSociety of Chemistry, 1999).

[0048] The colorant preparations according to the invention may includeas component (C) an organic solvent or a mixture of organic solvents, inwhich case these solvents may if desired possess a water-retainingeffect. Useful solvents include for example mono- or polyhydricalcohols, their ethers and esters, for example alkanols, especially of 1to 4 carbon atoms, for example methanol, ethanol, propanol, isopropanol,butanol, isobutanol; di- or trihydric alcohols, especially of 2 to 6carbon atoms, eg ethylene glycol, propylene glycol, 1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2,6-hexanetriol,glycerol, diethylene glycol, dipropylene glycol, triethylene glycol,polyethylene glycol, tripropylene glycol, polypropylene glycol; loweralkyl ethers of polyhydric alcohols, for example ethylene glycolmonomethyl or ethyl or butyl ethers, triethylene glycol monomethyl orethyl ethers; ketones and ketone alcohols, eg acetone, methyl ethylketone, diethyl ketone, methyl isobutyl ketone, methyl pentyl ketone,cyclopentanone, cyclohexanone, diacetone alcohol; amides, egdimethylformamide, dimethylacetamide and N-methylpyrrolidone.

[0049] The colorant preparations according to the invention may furtherinclude, as component (D), further, additives which are especiallycustomary for ink jet inks and in the printing and coatings industry,for example preservatives, antioxidants, cationic, anionic, amphotericor nonionic surface-active substances (surfactants and wetting agents),degassers/defoamers and also agents for regulating the viscosity, forexample polyvinyl alcohol, cellulose derivatives or water-solublenatural or artificial resins and polymers as film-formers or binders toenhance the adhesion and abrasion resistance. The pH regulators usedinclude organic or inorganic bases and acids. Preferred organic basesare amines, for example ethanolamine, diethanolamine, triethanolamine,N,N-dimethylethanolamine, diisopropyl-amine, aminomethylpropanol ordimethylaminomethylpropanol. Preferred inorganic bases are sodiumhydroxide, potassium hydroxide, lithium hydroxide or ammonia. Furtherconstituents include hydrotropic compounds, for example formamide, urea,tetramethylurea, ε-caprolactam, ethylene glycol, diethylene glycol,triethylene glycol, polyethylene glycol, butylglycol, methylcellosolve,glycerol, sugar, N-methylpyrrolidone,1,3-diethyl-2-methylimidazolidinone, thiodiglycol, sodiumbenzenesulfonate, sodium xylenesulfonate, sodium toluenesulfonate,sodium cumene-sulfonate, sodium benzoate, sodium salicylate or sodiumbutyl monoglycol sulfate.

[0050] Water used for the colorant preparation, component (E), ispreferably used in the form of distilled or demineralized water.

[0051] This invention further provides a process for producing thecolorant preparations according to the invention, which comprises afirst step of at least one colorant (component A), either as a powder oras a presscake, being pasted up together with at least one dispersingassistant (component B), optionally with at least one organic solvent(component C) and optionally the other additions (component D) inpreferably deionized water (component E) and subsequently homogenizedand predispersed using a dissolver or some other suitable apparatus.

[0052] If appropriate, a fine dispersion operation follows using a beadmill or some other suitable dispersing assembly to the desired particlesize distribution with cooling. After the fine dispersion operation, thedispersion can be diluted with deionized water to the desired colorantconcentration.

[0053] This invention further provides a set of colorant preparationsthat includes at least one colorant preparation in each of the colorsblack, cyan, magenta and yellow, characterized by at least one of thepreparations being a preparation according to the invention.

[0054] Preference is given to a set of pigment preparationscharacterized by the colorant of the black colorant preparation being acarbon black, especially a lampblack or a furnace black;

[0055] the colorant of the cyan colorant preparation being a pigmentfrom the group of the phthalocyanine pigments, especially the ColourIndex pigments P. Blue 15, P. Blue 15:3 or P. Blue 15:4,

[0056] the colorant of the magenta colorant dispersion being a pigmentfrom the group of the quinacridone pigments, preferably a Colour IndexP. Red 122 or P. Violet 19 or being a pigment from the group of themonoazo, disazo, isoindoline or benzimidazolone pigments, especially aColour Index P. Red 57:1, P. Red 146, P. Red 176, P. Red 184, P. Red 185or P. Red 269, and the colorant of the yellow colorant preparationpreferably being a pigment from the group of the monoazo, disazo,isoindoline or benzimidazolone pigments, especially the Colour Indexpigments Pigment Yellow 17, P. Yellow 74, P. Yellow 83, P. Yellow 97, P.Yellow 120, P. Yellow 128, P. Yellow 139, P. Yellow 151, P. Yellow 155,P. Yellow 180 or P. Yellow 213.

[0057] This invention further provides a set of printing inks thatincludes at least one printing ink in each of the colors black, cyan,magenta and yellow and is further characterized in that at least one ofthe printing inks includes the colorant preparation according to theinvention in neat or dilute form with or without further additives.

[0058] This invention yet further provides for the use of the colorantpreparations according to the invention as colorants for inks,especially ink jet inks, electrophotographic toners, especiallypolymerization toners, powder coatings and color filters.

[0059] By ink jet inks are meant not only waterborne inks (includingmicroemulsion inks) but also solventborne inks, UV-curable inks as wellas hotmelt inks.

[0060] Waterborne ink jet inks include essentially 0.5 to 30% by weightand preferably 1 to 15% by weight of one or more colorant preparationsaccording to the invention, 70 to 95% by weight of water, 0 to 30% byweight of one or more hydrotropic, ie water-containing, compounds and/ororganic solvents. Waterborne ink jet inks may optionally further includewater-soluble binders and further additives, for example surfactants andwetting agents, degassers/defoamers, preservatives and antioxidants.Microemulsion inks are based on organic solvents, water and optionallyan additional substance to act as an interface mediator (surfactant).Microemulsion inks include 0.5 to 30% by weight and preferably 1 to 15%by weight of one or more colorant preparations according to theinvention, 0.5 to 95% by weight of water and 0.5 to 95% by weight oforganic solvent and/or interface mediator.

[0061] Solventborne ink jet inks consist essentially of 0.5 to 30% byweight of one or more colorant preparations according to the invention,70 to 95% by weight of an organic solvent and/or of a hydrotropiccompound. If desired, solventborne ink jet inks may include carriermaterials and binders which are soluble in the solvent, for examplepolyolefins, natural and synthetic rubber, polyvinyl chloride, vinylchloride-vinyl acetate copolymers, polyvinyl butyrals, wax/latex systemsor combinations thereof.

[0062] UV-curable inks include essentially 0.5 to 30% by weight of oneor more colorant dispersions according to the invention, 0.5 to 95% byweight of water, 0.5 to 95% by weight of an organic solvent, 0.5 to 50%by weight of a radiation-curable binder and optionally 0 to 10% byweight of a photoinitiator.

[0063] Hot melt inks are usually based on waxes, fatty acids, fattyalcohols or sulfonamides which are solid at room temperature and liquefyon heating, the preferred melting range being between about 60 and about140° C. This invention also provides a hot melt ink jet ink consistingessentially of 20 to 90% by weight of wax and 1 to 15% by weight of oneor more colorant preparations according to the invention. It may furtherinclude 0 to 20% by weight of an additional polymer (as “dyedissolver”), 0 to 5% by weight of dispersing assistant, 0 to 20% byweight of viscosity modifier, 0 to 20% by weight of plasticizer, 0 to10% by weight of tack additive, 0 to 10% by weight of transparencystabilizer (which prevents for example crystallization of the wax) andalso 0 to 2% by weight of antioxidant. Typical additives and auxiliariesare described for example in U.S. Pat. No. 5,560,760.

[0064] The ink jet inks according to the invention can be prepared bydispersing the colorant preparations into the microemulsion medium orinto the aqueous or nonaqueous medium or into the medium for preparingthe UV-curable ink or into the wax for preparing the hot melt ink jetink.

[0065] As well as for printing paper, natural or synthetic fibermaterials, films or plastics, the colorant preparations according to theinvention can be used for printing a wide variety of coated or uncoatedsubstrate materials, for example for printing paperboard, cardboard,wood and woodbase materials, metallic materials, semiconductormaterials, ceramic materials, glasses, glass and ceramic fibers,inorganic materials of construction, concrete, leather, comestibles,cosmetics, skin and hair. The substrate material can betwo-dimensionally planar or extend in space, ie be three-dimensional,and be printed or coated completely or only in parts.

[0066] It has been determined that the colorant preparations accordingto the invention have altogether advantageous application properties andoptimally fulfil the aforementioned offices and requirements in ink jetprinting. The viscosity remains stable not only at room temperature butalso in the course of one weeks of storage at 60° C. and the particlesize distribution changes only insignificantly during storage. The inksproduced from the preparations are notable especially for markedly goodbehavior in ink jet printing due to good stability during storage and inthe ink jet printing operation. Moreover, the prints produced arenotable for their high light and water fastness.

[0067] The colorant preparations according to the invention are alsouseful as colorants in electrophotographic toners and developers, forexample one component and two component powder toners or developers,magnetic toners, liquid toners, polymerization toners and also otherspecialty toners. Typical toner binders are addition polymerization,polyaddition and polycondensation resins, eg styrene, styrene-acrylate,styrene-butadiene, acrylate, polyester or phenolic epoxy resins,poloysulfones and polyurethanes, individually or in combination, andalso polyethylene and polypropylene, which may include yet furtheringredients, such as charge control agents, waxes or flow agents, or mayhave added to them subsequently.

[0068] The colorant preparations according to the invention are furtheruseful as colorants in powder coatings, especially in triboelectricallyor electrostatically sprayed powder coatings which are used for surfacecoating articles made for example of metal, wood, plastic, glass,ceramic, concrete, textile material, paper or rubber. Useful powdercoating resins typically include epoxy resins, carboxyl- andhydroxyl-containing polyester resins, polyurethanes and acrylic resintogether with customary hardeners. Combinations of resins are also used.For instance, epoxy resins are frequently used in combination withcarboxyl- and hydroxyl-containing polyester resins. Typical hardenercomponents (depending on the resin system) are for example acidanhydrides, imidazoles and also dicyandiamide and their derivatives,capped isocyantes, bisacylurethanes, phenolic and melamine resins,triglycidyl isocyanurates, oxazolines and dicarboxylic acids.

[0069] The colorant preparations according to the invention are alsouseful as colorants for color filters and also for additive as well assubtractive color generation.

EXAMPLES

[0070] I Production of a Pigment Preparation (General Prescription):

[0071] The pigment, either as a powder or as a presscake, was pasted uptogether with the dispersant, the organic solvent and the otheradditives in deionized water and then homogenized and predispersed usinga dissolver. The subsequent fine dispersion was effected using a beadmill, the grinding being effected with cooling to the desired pigmentparticle size distribution. Subsequently, the dispersion was adjustedwith deionized water to the desired final pigment concentration.

[0072] The pigment preparations described in the examples hereinbelowwere produced by the above-described process:

Examples Nos. 1 to 4

[0073] (see Table 1) Ink jet preparation comprising: 15% by weight ofpigment 5% by weight of dispersant 1 10% by weight of propylene glycol1% by weight of defoamer (® Dehydran 975 from Cognis) 69% by weight ofwater

[0074] TABLE 1 Example No.: Pigment 1 C.I. P. Blue 15:3 2 C.I. P. Red122 3 C.I. P. Yellow 155 4 C.I. P. Black 7

[0075] Dispersant 1 consists of a mixture of an alkoxylated naphthol ofthe formula (III) and of a sulfopropylated alkoxylated naphthol of theformula (IV).

[0076] The conditions for the parameters m, n and X are:

[0077] m=2.5 on average

[0078] n=14 on average

[0079] X=potassium ion

[0080] Owing to the synthesis (sulfopropylation reaction) dispersant 1contains about 20% by weight of molecules of the formula (III) and about80% by weight of molecules of the formula (IV).

Examples No. 5 to 8

[0081] (see Table 2) Ink jet preparation comprising: 15% by weight ofpigment 5% by weight of dispersant 2 10% by weight of propylene glycol1% by weight of defoamer (® SERDAS 7010 from CONDEA) 69% by weight ofwater

[0082] TABLE 2 Example No.: Pigment 5 C.I. P. Blue 15:3 6 C.I. P. Red122 7 C.I. P. Yellow 120 8 C.I. P. Yellow 155

Examples No. 9 to 12

[0083] (see Table 3) Ink jet preparation comprising: 15% by weight ofpigment 5% by weight of dispersant 3 10% by weight of propylene glycol1% by weight of defoamer (® SERDAS 7010 from CONDEA) 69% by weight ofwater

[0084] TABLE 3 Example No.: Pigment 9 C.I. P. Blue 15:3 10 C.I. P. Red122 11 C.I. P. Yellow 120 12 C.I. P. Yellow 155

[0085] Dispersants 2 and 3 each consist of mixtures of alkoxylatedalkanols of the formula (V) and sulfopropylated alkoxylated alkanols ofthe formula (VI)

[0086] Owing to the synthesis (sulfopropylation reaction) thedispersants 2 and 3 contain about 15% by weight of molecules of theformula (V) and about 85% by weight of molecules of the formula (VI);the conditions for dispersant 2 are:

[0087] R4=mixture of about 60% by weight of tridecanyl (C₁₃H₂₇), about10% by weight of tetradecanyl (C₁₄H₂₉) and about 30% by weight ofpentadecanyl (C₁₅H₃₁)

[0088] m=0

[0089] n=7 on average

[0090] X=potassium ion

[0091] while the conditions for dispersant 3 are as follows:

[0092] R4=mixture of about 60% by weight of tridecanyl (C₁₃H₂₇), about10% by weight of tetradecanyl (C₁₄H₂₉) and about 30% by weight ofpentadecanyl (C₁₅H₃₁)

[0093] m=0

[0094] n=11 on average

[0095] X=potassium ion

[0096] II Investigation of Physical Properties of Pigment PreparationsMentioned in the Examples 1 to 12:

[0097] The physical properties of the pigment preparations wereinvestigated using the following methods and equipment:

[0098] II.1 Viscosity Measurement (Dynamic Viscosity)

[0099] The viscosity was determined using a Haake (Roto Visco 1)cone-plate viscometer (titanium cone: Ø 60 mm, 1°) by investigating thedependence of the viscosity on the shear rate in a range between 0 and700 1/s. The viscosity values mentioned in the table were measured at ashear rate of 400 1/s. To evaluate the storage stability of thedispersions, the effect of the storage time and of the storagetemperature on the viscosity was investigated. To this end, theviscosity was measured (1) directly after production of the preparation,(2) after one week of storage at room temperature (25° C.) and (3) afterone week of storage at 60° C.

[0100] II.2 Particle Sizes

[0101] The particle sizes of the preparations (D₅₀ values) weredetermined by the capillary hydrodynamic fractioning (CHDF) methodfollowing one week of storage at 25 or 60° C. In the case of stabledispersions, no coagulation of the pigment particles should take placeregardless of the storage conditions; more particularly, the storagetemperature should have little if any influence on particle size.

[0102] Table 4 hereinbelow gives an overview of the physical propertiesof the various pigment preparations mentioned in the examples: TABLE 4Exam- Viscosity [mPas] D₅₀ [nm] ple η[25° C.] η[25° C.]_(1 week) η[60°C.]_(1 week) 25° C. 60° C. 1 5.5 5.3 5.9 85.0 97.4 2 6.5 6.1 7.0 88.491.4 3 9.4 10.5 6.8 134.4 129.2 4 11.6 13.1 22.9 82.3 100.2 5 7.2 7.37.4 89.3 95.7 6 7.3 7.0 10.8 78.5 82.2 7 11.3 17.0 30.3 127.1 96.9 8 6.96.8 6.5 99.2 101.5 9 10.9 10.8 10.7 84.9 86.2 10 11.2 10.4 10.5 82.288.7 11 9.3 8.6 8.7 96.7 99.9 12 11.6 11.5 9.8 115.3 109.4

[0103] All the examples of pigment preparations according to theinvention that are listed in Table 4 possess excellent flowability. Toevaluate their stability in storage, first the viscosities η[25° C.] ofthe freshly produced preparations were measured (cf. Table 5).Thereafter, the preparations were each stored for one week at 25 or 60°C. and subsequently the viscosities η[25° C.]₁ week and η[60°C.]_(1 week) of the dispersions stored at 25 and 60° C. respectivelywere determined. In the case of very stable dispersions, the viscositiesshould not change from the original viscosity. The measured results inTable 4 show that only very minimal viscosity changes occur as a resultof storage and that the dispersions are accordingly all stable.

[0104] The D₅₀ values reported in Table 4 show that only small changesin the average particle sizes occur in all cases. Thus, the pigmentparticles do not coagulate in the course of storage, indicating verygood stability in storage on the part of the dispersions. Furthermore,some of the dispersions were stored at 60° C. for 4 weeks (eg thepigment preparations of examples 1, 2, 3 and 4) in no case was adispersion observed to flocculate. Even longer storage periods wereinvestigated at room temperature. Here, there were no signs ofsedimentation whatsoever even after 3 months, indicating a very highstability on the part of the dispersions produced. Even aqueousdilutions of these pigment concentrates to a pigment content of 3%display the same stability features.

[0105] III Testing of Printing Properties of Pigment Preparations

[0106] Knowledge of the physical properties of pigment preparationsalone is not sufficient to make a statement about their suitability forink jet printing. In thermal ink jet (bubble jet) printing especially,the behavior of the pigment dispersions during the printing process inthe nozzles is important. The large albeit brief thermal stresses mustnot cause the pigment dispersion to decompose, for example in that thedispersant molecules desorb from the pigment surface because this wouldcause the pigment particles to agglomerate. Such decomposition processescould on the one hand lead to cogation and on the other over time tonozzle clogging by the decomposition products.

[0107] The suitability of pigment preparations for producing inks forthe ink jet process can thus only be judged by carrying out printingtests. To evaluate the printing properties of the pigment preparations,the preparations were used to produce test inks whose printability wasinvestigated using a thermal ink jet printer (cf. Table 5).

[0108] To produce the test inks, the pigment preparations were initiallyfinely filtered through a 1 μm filter to remove grinding media attritusand any coarse fractions. Thereafter, the filtered preparations werediluted with water and admixed with further low molecular weightalcohols and polyols. The test inks then have the following composition:33.33% of pigment preparation (Examples 1 to 12) 46.67% of demineralizedwater   10% of ethylene glycol   10% of diethylene glycol

[0109] The composition of the test inks was chosen so that the viscositywas in a range from 1.5 to 5 mpas. To adjust the surface tension of theinks to a value needed for optimum printing performance, small amountsof surfactants can be admixed if necessary.

[0110] The test inks were characterized using the following methods andequipment:

[0111] III.1 Print Head Jet Formation Behavior of Ink

[0112] An HP print RIG with Optica System from Vision Jet was used toinvestigate the behavior of the test inks in ink jet printing using anHP 420 thermal ink jet printer from HP. A video camera can be used toinvestigate the behavior of the injkets during the printing operation atindividual nozzles of the ink jet print head. The video images provideinformation as to how the pigmented ink behaves in the course of theformation of the ink jets, whether the ink is expelled from the nozzlesof the print head in the form of straight, linear jets, whetherindividual drops are formed or whether the drops have satellites. Theinvestigations provide additional information on the shape of ink dropsand indicate irregularities in drop formation, for example due tocloggages of individual nozzles.

[0113] The inks investigated possess a very good jet formation behavior,as is discernible from the fact that the individual ink jets areparallel and leave the nozzles at right angles to the surface. None ofthe nozzles is clogged. Jet and drop formation is very uniform in thatindividual drops are formed from the ink jets over time without smallersatellite droplets being observed.

[0114] III.2 Investigation of Printing Behavior

[0115] In addition, the HP 420 printer was used to print test images oncommercially available normal papers (copy papers) and specialty papers(premium quality) from HP. The evaluation of the prints with regard toquality and finish of the printed image was done by purely visualinspection. It was noted whether the paper was greatly moistened,whether the pigment penetrated into the paper or whether the pigmentremained stuck to the surface of the paper. It was further noted to whatextent fine lines were perfectly reproduced, whether the ink spread outon the paper, resulting in low resolution, or whether it was possible toproduce high resolution prints. The start of print behavior wasinvestigated after prolonged pauses in the printing to see whether agood and flawless print was ensured instantly or whether individualnozzles channels were clogged by the ink drying, which led to a poorprinted image.

[0116] The criteria (III.1) and (III.2) were used to evaluate the printquality of the inks on the following scale from 1 to 6 (cf. Table 5):

[0117] 1—Very good printed image, lovely uniform jet and drop formation

[0118] 2—Very good printed image, uniform jet but nonuniform dropformation

[0119] 3—Good printed image, nonuniform jet and drop formation

[0120] 4—Nonuniform fuzzy printed image, random orientation of ink jetsand drops

[0121] 5—Poor, stripy printed image, individual nozzles clogged

[0122] 6—Ink will not print, all nozzles clogged very quickly TABLE 5Example Print quality 1 2-3 2 1 3 1-2 4 1 5 1 6 1 7 2-3 8 2 9 3 10 1 112-3 12 2

[0123] The pigment preparations fully meet the ink jet printingrequirements with regard to physical and printing properties and so areparticularly useful for applications in ink jet printing.

1. An aqueous colorant preparation comprising: A) 0.1 to 50% by weightof at least one organic and/or inorganic pigment and/or at least oneorganic dye, B) 0.01 to 80% by weight of at least one naphtholalkoxylate sulfopropyl ether, alkanol alkoxylate sulfopropyl ether oralkylphenol alkoxylate sulfopropyl ether, C) 0 to 30% by weight of atleast one organic solvent, D) 0 to 20% by weight of at least oneadditive, E) 10 to 90% by weight of water, each percentage being basedon the total weight (100% by weight) of the colorant preparation.
 2. Anaqueous colorant preparation as claimed in claim 1, wherein component(A) is a monoazo, disazo, laked azo, β-naphthol, Naphtol AS,benzimidazolone, disazo condensation, azo metal complex, phthalocyanine,quinacridone, perylene, perinone, thiazineindigo, thioindigo,anthanthrone, anthraquinone, flavanthrone, indanthrone, isoviolanthrone,pyranthrone, dioxazine, quinophthalone, isoindolinone, isoindoline,diketopyrrolopyrrole pigment or a carbon black pigment.
 3. An aqueouscolorant preparation as claimed in claim 1, wherein component (A) is aColour Index dye Acid Yellow 17, Acid Yellow 23, Direct Yellow 86,Direct Yellow 98, Direct Yellow 132, Reactive Yellow 37, Acid Red 52,Acid Red 289, Reactive Red 23, Reactive Red 180, Acid Blue 9, DirectBlue 199 or a mixture thereof.
 4. An aqueous colorant preparation asclaimed in claim 1, wherein component (B) is a compound of the formula(II) or a mixture of a compound of formula (II) with a compound of theformula (I)

where R1 and R2 are identical or different and are each a C₁-C₁₂-alkylradical which may contain polar groups such as alcohol groups, aminegroups, keto groups, amide groups or ester groups, or are each a phenylradical or H, R3 is a C₁-C₄-alkyl radical or a phenyl radical, m is from0 to 50, n is from 1 to 100, subject to the proviso that n≧m; X is asingly positively charged ion.
 5. An aqueous colorant preparation asclaimed in claim 1, wherein component (B) is a compound of the formula(VI) or a mixture of a compound of (VI) with a compound of the formula(V)

where R4 is R5 or

R5 is a C₁-C₂₄-alkyl radical which may contain polar groups m is from 0to 50, n is from 1 to 100, X is a singly positively charged ion.
 6. Aprocess for producing an aqueous colorant preparation as claimed inclaim 1 comprising the steps of mixing component A with at least onedispersant (component B) in water (component E) to form a paste andhomogenizing the paste.
 7. A colorant for printing inks, ink jet inks,electrophotographic toners, polymerization toners, powder coatings andcolor filters comprising an aqueous color preparation as claimed inclaim
 1. 8. A set of colorant preparations comprising at least onecolorant preparation in each of the colors black, cyan, magenta andyellow, wherein at least one of the preparations is an aqueous colorantpreparation as claimed in claim
 1. 9. A set as claimed in claim 8,wherein the colorant of the black colorant preparation is a carbonblack, the colorant of the cyan colorant preparation being a pigmentselected from the group consisting of phthalocyanine pigments, thecolorant of the magenta colorant preparation is a pigment selected fromthe group consisting of quinacridone pigments, monoazo, disazo,isoindoline and benzimidazolone pigments, and the colorant of the yellowcolorant preparation is a pigment selected from the group consisting ofmonoazo-, disazo-, and benzimidazolone pigments.
 10. A printing inkcomprising the set of colorant preparations as claimed in claim
 8. 11.An aqueous colorant preparation as claimed in claim 4, wherein X is theion of an alkali metal, a hydrogen ion, an ammonium ion, or a mono-, di-tri- or tetraalkylammonium ion.
 12. An aqueous colorant preparation asclaimed in claim 5, wherein R5 is a C₁-C₂₄-alkyl radical containingpolar groups, wherein the polar groups are selected from the groupconsisting of alcohol groups, amine groups, keto groups, amide groupsand ester groups.
 13. An aqueous colorant preparation as claimed inclaim 5, wherein X is the ion of an alkali metal, a hydrogen ion, anammonium ion or a mono-, di-, tri- or tetraalkylammonium ion.
 14. Theprocess as claimed in claim 6, wherein the mixing step further comprisesadding at least one organic solvent (component C) to the paste.
 15. Theprocess as claimed in claim 6, wherein the mixing step further comprisesadding at least one additive (component D) to the paste.
 16. The processas claimed in claim 6, further comprising the step of dispersing thepaste.
 17. The set as claimed in claim 9, wherein the colorant of theblack colorant preparation is selected from the group consisting oflampblack and furnace black, wherein the colorant of the cyan colorantpreparation is a pigment selected from the group consisting of ColourIndex P. Blue 15, P. Blue 15:3 and P. Blue 15:4, wherein the color ofthe magenta colorant preparation is a pigment selected from the groupconsisting of Colour Index P. Red 122, P. Violet 19, P. Red 57:1, P. Red146, P. Red 176, P. Red 184, P. Red 185 and P. Red 269, and wherein thecolorant of the yellow colorant preparation is a pigment selected fromthe group consisting of Colour Index P. Yellow 17, P. Yellow 74, P.Yellow 83, P. Yellow 97, P. Yellow 120, P. Yellow 128, P. Yellow 139, P.Yellow 151, P. Yellow 155, P. Yellow 180 and P. Yellow
 213. 18. An inkjet ink comprising the set of colorant preparations as claimed in claim8.